Compass



y 3, 1963 H. N. HARRIS 3,098,304

COMPASS Filed April 5, 1961 Harlan M Harris INVENTOR.

United States Patent 3,098,304 COMPASS Harlan N. Harris, 1850 N. Avenue 51, Los Angeles, Calif. Filed Apr. 5, 1961, Ser. No. 101,016 Claims. (Cl. 33-154) The present invention relates generally to improvements in compasses.

One object of my invention is to provide a stop for limiting the spread of the compass legs.

My invention has other objects which will be evident from a study of the following specification read in connection with the accompanying drawings, in which one form of my invention is shown.

Referring to the drawings:

FIG. 1 is an upright front view of the compass.

FIG. 2 is an upright side view of the compass.

FIG. 3 is an upright front view of the compass showing the legs at their maximum spread and the position of the stop.

Referring to FIGS. 1, 2 and 3, the numeral 11 indicates a hinge pin which carries the upper ends of a pair of legs 12 and 13, said legs being held in grooves in the hinge pin 11 by a C-spring 14. A handle 15 is pressed or otherwise secured on one end of a shaft 16 which passes through a hole in the spring .14 and is firmly secured in the hinge pin 11 with a part of the shaft, as indicated by the numeral 17, extending below the hinge pin.

In order to adjust the spread of the compass legs, a center-screw 18 is provided which can be turned by means of a thumb-piece 19. The threads of the center-screw 18 are left-handed on one side of the thumb-piece 19 and right-handed on the other. The center-screw 18 is articulated with the legs 12 and 13- by means of cylindrical nuts 20 and 2.1, respectively. Each of these nuts fits smoothly in holes 22 in the two legs. Transverse holes through the nuts 20 and 2 1 are threaded to receive the center-screw 18. In passing through each of the nuts, the center-screw at the same time passes through the corresponding leg.

The lower end of each leg is provided with a clamp, operated by the screw 23, which can be used to hold either a pencil lead, or a steel point. The clamp can also be used to hold the tang of a suitably designed pen so that circles can be drawn in ink.

As the compass legs are spread apart by turning the thumb-piece 19, the thumb-piece and the part 17 of the shaft extending below the hinge pin will be relatively moved towards each other and into closer proximity. At the same time, the nuts 20 and 21 are approaching the ends of the center-screw 18. Now referring to FIG. 3, it is obvious that if part 17 is constructed of proper length, the thumb-piece 19 will move into contact with it just as the ends of the center-screw are about to enter the nuts 29 and 21. Further spreading of the legs is thus terminated and the ends of the center-screw restrained from being drawn through and disengaged from the nuts. In the event of such disengagement, the legs would be out of control, and their upper ends could be disengaged from the hinge pin 11.

Heretofore, in conventional compass constructions, complete vw'thdrawal of the ends of the center-screw 18 through the nuts 20 and 21 has been prevented by utilizing one or more of three expedients: (1) the operator has 3,098,304 Patented July 23, 1963 ice exercised care against such withdrawal; (2) the centerscrew has been made very long; and (3) limiting stops have been put on one or both ends of the center-screw. These stops may take one of several forms. For example, knobs may be soldered or riveted to the screw; the screw ends may be split and spread apart; a pin may be driven through a transverse hole adjacent the screw end; or the threads adjacent a screw end may be battered. Each of these approaches to the problem solution is undesirable and inherently subject to one or more of the following objections: (1) difiiculties in construction; (2) unattractive in appearance; and (3) ineffectiveness in performance.

The herein described invention overcome-s the above objections and obtains its stated and other desirable objects by providing a simple construction of neat appearance, and which is effective and efficient in operation.

This described embodiment, except for the clamp screws 23, also prevents disassembly of the interconnected parts without first releasing the C-spring 14, an operation requiring a special tool. It thus affords insurance against the inadvertent loss of parts.

Other advantages and the use and operation of the compass of my invention will readily be understood by those skilled in the art to which the invention appertains. While I have described one form of my invention for purposes of illustration, I desire to have it understood that the invention is not to be limited to the details disclosed herein, but is to be accorded the full scope of the appended claims.

I claim:

1. A compass, comprising: a pair of leg members; hinge means connecting said members at corresponding ends for swinging movements; an adjustable articulate connection between points on said legs spaced from said hinge means for varying the angular relationship of said legs, said hinge means being relatively movable towards said connection as the angular relationship of said legs is increased; and a part carried by said hinge means for abutment with said connection to limit the maximum angular separation of said legs.

2. A compass, comprising: a pair of leg members; hinge means connecting said members at corresponding ends for swinging movements; an adjustable screw connection between points on said legs spaced from said hinge means including a centrally positioned thumb-piece for rotating said screw to vary the angular relationship of said legs, said hinge means being relatively movable towards said connection as the angular relationship of said legs is increased; and a part carried by said hinge means for abutment with said thumb-piece to limit the maximum angular separation of said legs.

3. A compass, comprising: a pair of leg members; hinge means connecting said members at corresponding ends for swinging movements; an adjustable articulate connection between points on said legs spaced from said hinge means for varying the angular relationship of said legs, said hinge means being relatively movable towards said connection as the angular relationship of said legs is increased; an a pin carried by said hinge means having an end positioned for abutment with said connection at a predetermined maximum angular separation of said legs.

4. A compass, comprising: a pair of leg members; hinge means connecting said members at corresponding ends for swinging movements and including a pin member extending between and bisecting the angle between said legs during hinge movements thereof; and means for adjusting the angular relationship of said legs including a screw having its opposite ends respectively connected with said legs between their ends, said pin having a length and direction to engage said adjusting means and limit the maximum angle of adjustment of said legs.

5. A compass, comprising: a pair of legs joined at their upper ends by a hinge device; an adjusting screw engaging each of said legs intermediate the ends thereof; a centrally positioned thumb-piece for rotating said screw -for controlling the spread of the lower ends of said legs; and a pin aftixed to said hinge device and so projecting toward said thumb-piece as to be brought to bear against it as the spread of the lower ends of said legs is increased, whereby to establish a limit for such spread.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A COMPASS, COMPRISING: A PAIR OF LEG MEMBERS; HINGE MEANS CONNECTING SAID MEMBERS AT CORRESPONDING ENDS FOR SWINGING MOVEMENTS; AM ADJUSTABLE ARTICULATE CONNECTION BETWEEN POINTS ON SAID LEGS SPACED FROM SAID HINGE MEANS FOR VARYING THE ANGULAR RELATIONSHIP OF SAID LEGS, SAID HINGE MEANS BEING RELATIVELY MOVABLE TOWARDS SAID CONNECTION AS THE ANGULAR RELATIONSHIP OF SAID LEGS IS INCREASED; AND A PART CARRIED BY SAID HINGE MEANS FOR ABUTMENT WITH SAID CONNECTION TO LIMIT THE MAXIMUM ANGULAR SEPARATION OF SAID LEGS. 